Thread-cutting mechanism



May 13, 1952 H. H. RANNEY THREAD-CUTTING MECHANISM 5 Sheets-Sheet 1 Filed May 16, 1947 liwi/Zfwazzg H. H. RANNEY 2,596,723

THREAD-CUTTING MECHANISM 5 Sheets-Sheet 2 May 13, 1952 Filed May 16, 154'! May 13, 1952 H. H. RANNEY THREAD-CUTTING MECHANISM 5 Sheets-Sheet 3 Filed May 16, 1947 7 H. H. RANNEY THREAD-CUTTING MECHANISM May 13, 1952 5 Sheets-Sheet 4 Filed May 16, 1947 May 13, 1952 H; H. 'RANNEY 2,596,723

THREAD-CUTTING MECHANISM Filed May 16, 1947 5 Sheets-Sheet 5 122M227 Z/WZWZ JZZm/Z w w Patented May 13, 1952 star-Estates This invention relates to mechanisnrifor cutting:

threads, either internal or external andhasfor? an object to provide suchsa.mechanismi'applicabler as an attachment for. a multiple spindler'lathes for cutting threads at oneor more ofrtliertooling: 5

stations.

A further objectis to increase the: accuracy: of thread cutting by. controllinglthe':tolebys'a lead screw and nut.

Still another object is; to -providei a thread cutting mechanism in'which' lead screw of iva'rious forms may be used-selectively dependingmpon the type and leadof threa'dsiwhichrit is 'desiredi to cut.

Claims (ems-51) Figure 13 is aview similar to- Figure- 4} but showing ahead for external-thread milling.

Figures 14 and: 16 are sectional views 1 on lines M and I S! 6', respectively, of Figure 13;

Eigure lii is -a i front end-elevation ofthe head ofxFigureszlS and 1 4.

Eigure lf? is a view similar to Figure'49but. showing a modification for internal thread chas mg;

Figures 18% and 19: are" detail-sectional view's 'onl lines i8-IS and l9-l9, respectively, of Figurelm Figure 20 is" a view similar to aportion-- of Figure l; but showing fa modifiedconstruction:

Figure 21 isa fragmentary view partly in sidei Still another object is to provide adiustr'nent v a p t vb k swam-thr u h a- -work of the axial position ofth'ellead*screwsot-that threads may be cut at-thedesiredv'axialr portion of the work and-' yet avoid the necessity .r ofan excessively longv lead' screw in order: toicoverthe range of axial positions-J wherthreadficuttiirgi may be desired.

A further object of the invention-E ta pro vide, if desired, for the use of a rotary milling: cutter driven-from the drivel mechanism of the piece-andshowingian internal thread cutting tool at the-start of thethread cutting operation, the toel being; shown in dotted lines somewhat retracted.

Figure 22-is a View similar to Figure 21, but showing cu-tting;- of external threads.

Figure 23-is exploded perspective view showing a non-rotatirig-cuttirig tool or chaser, as

ire-Figure-li; and the spindle end on which the machine for cutting the: threads;' al thoug-lia chaser-is mounted; I

non-rotating chaser maybe us'ed instead iof -I the rotary cutter if I desired."

Further objects and adi'i antage's w-il-l' appear from a description of -certain einbo nienlisaoi ings in which:- a v Figure 1 is afragmentary frontelevation pai'tly broken away and insection of multiple spindle lathe embodying the invention as appiied to"in ternal thread 'millin'ga" Figures 2 and 3 are detailfsectionalfvi vs on" lines 22 and 3 3, respectively; Of":F igure Figure 4 is a-fragmentary central sectional View through the head portion-*of the threading? attachment. I

Figures 5, 6 and"? are detairsectional views" taken on the correspondingly numbered section lines of Figure 4, Figures fia-nd f being-drawn to f larger scale and Figure 5"alsobeinga"sectional View on line 55 of-"Figure f7'.- I v Figure 8 is'a' central longitudinaFsectional view of the portion'of' themeclranism' to"the" rear of that shown in Figures.

Figure 9 is a somewhat diagrammatid'vie'wto'" This invention hasbeen illustratedas embodiedin anr-attachment to-a multiple spindle latheof" the wel-l-known Cone type in which the"w0rk-'-' holding; spindles are-arranged in circularseries the invention shewn-intne atccmeansing ebwitheaXis-Ofe Spindle Carrier, this Carrie? mg indexedto bring the spindles successively'into Various-tooling. positions.- This attachment may be-applied at any of-thetooling positions desired. One of the work-spindles is shown as support 3g ing aworiepiece a-t lin-Figure 1 at'one' tooling" station. Thework spindles are rotated by: any

suitable'meansand a portion of the drive means 1 for such rotation comprises a shaft 2 arranged coaxial with the" spindle carrier and from which 1 9s the spindles are"rotated; asby geared connections as-iswelrknown in the-art.v slidable'axiallyof thief-shaft- 2 tis'a tool slideS of well known" oer-1'- struction provided with longitt'i'dina11y extending- Tslot ways i inii tsper-ipheryas shown 'in Fig'ure2 these slots beingian'gularly spaced iii-accordance with the spacingof the spindles in thespi-ndle carrier; Gne'ot these slots 4 1s shown asprovided with? a guide piec fi secured as by T nuts" Band" guid pieceihasslidablybearin'g a larger scale of aportion-cfthelead screw x: 13159396113laislfitiiiguifl" p tion Bbf a yOKeS, this:

edeta-ii sect-iona-Pviews" on the correspondingl y- 'nturibered sectien lines of Figure 8'.

yoke 9 thus being held against rotation, but being capable of sliding motion axially: along "the guide rigs-tee) "Between-an end flange i i thereof and" a collar 12 pinned to a nut l3, threaded on one end portion of the sleeve H3. The sleeve H) is carried by a quill l which extends in the direction of the work spindles, and as shown, is coaxial with one of them at one of the tooling stations. The quill I5 is longitudinally slotted as at it. To the rear face of the end flange N there is secured, as by screws 20, a ring 2| (see Figure having guide portions 22 extending inwardly through the slots l6 through the quill 15, this ring 2| being secured as by screws 23 to the rear end of a tool spindle 24 coaxial within the quill l5. Within the guide portions 22 are positioned opposed nut segments 25 which are movable radially toward and from a lead screw 26 having a threaded end portion 21 and a reduced diameter shank 28. These segments are held in their guideways by a ring 29 secured as by screws to the outer end of the spindle 24, as best shown in Figure 12. Each of these segments 25 has a rearwardly extending pin 30 which rides in an angle slot 3| in a ring 32. The angle slots 3| are so positioned that when the pins ride in the inner portions of these slots, the segments 25 are positioned inwardly so related that when the threaded portion 21 of the lead screw is opposite'thereto, they are in driven relation to the lead screw. In the position shown in Figure 8, the spindle 24 is retracted and the lead screw portion 21 is out of driving relation to these nut segments.

' The ring 32 is normally urged away from the angular position shown in Figure 11 by a spring 35 seated in a socket in the ring 32 and pressing a plunger 36 against a pin 31. This pin 3'! rides in a slot 38 through the ring 32 and projects forwardly from a collar 40, having a circular marginal flange portion 4| which encloses the ring 32, the segments and their guideways, and the flange relative to the spindle 24 by being secured, as by screws 42 (see Figure 12), to a portion of the member 2| which, in turn, is keyed to the spindle 24 by means of the portion 22 which extends through the quill slots 16. This member is slidable axially with its assembly on the outside of the spindle 24 and has threaded on its rear end a collar 45 which projects over and inwardly toward a spool 45. This spool 45 is slidable axially on the quill between its position abutting the member 40 shown, and a retracted position where an annular external shoulder 41 thereon abuts the in-turned flange 48 of the collar 45. Carried by the spool 46 are a pair of conical ended plugs 50 which are slidable through openings 5| through the member 40, these plugs thus acting to key the spool against relative rotation with respect to the member 40. The conical inner ends of these plugs may engage in bushed openings 52 through the ring 32. When these plugs 5| are engaged in these bushings, the ring 32 is held in the position shown in Figure 11 with the pins 3!] in the inner portions of the slots 3| and with the segments 25 locked in their inward positions where they will engage the threaded portion 21 of the lead screw when this portion is opposite to the segments. By withdrawing the spool 46 longitudinally, however, these pins 50 may be withdrawn from the bushings 52, whereupon the spring 35 turns the ring 32 to bring the pins 30 toward the outer ends of the slots 3|, causing the segments to spring outwardly into inoperative positions. This angular extent of motion of the ring 32 is insufficient to bring the bushings 52 entirely out This flange 4| is held from rotation a of registry with the conical ends of the plugs 50 so that on returning the spool 46 to its former position these tapered ends wedge the ring 32 to rock it about its axis and move the segments 25 into operative positions. When in these positions cylindrical portions of the plugs 55 engage within the bushings and act to lock the segments in position.

The lead screw 26 may be adjustably held in the desired axial position so that the segments will engage its threaded portion at the position where a thread cutting tool is in proper relation to the work, as will later appear, and in order that the lead screw may be so held, it is carried in a spring collet 60 (see Figure 8) which is attached to a sleeve 6|, this sleeve extending through a hollow shaft 62 which is journaled in a frame portion 63 of the machine against axial motion. The outer end of the sleeve 6| is provided with an enlarged diameter portion 64 (Figure 1) which engages a washer 65 opposite to the end of the shaft 52, and this enlarged portion 54 is provided with transverse perforations 55 through which a tool may be inserted to permit rotation of the sleeve Bl, this rotation acting on the threaded connection at 61 with the collect 62 so as to either free it or clamp it against the shank 28 of the lead screw by reason of the mating inclined faces 68 and 69 of the collect and shaft 62, respectively.

The rear end of the shank 28 may have a threaded socket It (Figure 8) into which may be screwed the forward end of a rod (not shown) which may extend out through the rear end of the shaft 62 and by manipulation of which the lead screw may be moved axially when the collet 69 has been released so that when the threaded portion 21 of the lead screw has been positioned at the desired point, the collet 60 may again be tightened up and the lead screw held against axial sliding motion. The rod engaged in the socket it may then be removed from the machine.

It is, of course, necessary that a relative rotation between the lead screw and the segments 25 shall take place in order to produce axial motion of the tool spindle to-produce the lead of the threads. To this end the shaft 62 is arranged to be rotated from the shaft 2 by which the work spindles are driven and at the same speed. This is accomplished by means of the intermeshing gears 12 and 13, respectively, carried by the shaft 2 and the shaft 62. The tool spindle is rotated from the shaft 62 but at a different speed in order to produce the lead from the relative rotation between the lead screw and its nut segments. For this purpose, the shaft 62 has keyed thereto a gear .14 which meshes with a pinion i5 carried by a stub shaft 15. This stub shaft 15 also carries a pinion H which meshes with a gear portion 18 at the rear end of the quill [5. This quill is also journaled on the forward end of the shaft 62 on the ball bearings 19. It will be noted that the gears 14 and 18 are of different size and mesh with gears 15 and 1'! which are also of different size, and by reason of this the quill, and through the members 22, the spindle 24, also, and the shaft 62 are driven at a differential velocity.

The head which carries the nut segments and the tool spindle 24 is moved to bring the threading tool to the proper place longitudinally on the work for threading operation and to bring the nut segments 25 into controlled relation to the threaded portion of the lead screw by yielding mechanism connected-to the yoke, 9. As-shown: in I Figure; 1, this comprises a linl v 85 whichhis pivotally connected to :thellyok'e 9.at its,rearl end andLhasa spring 86 at it's forwardr end; seated.-

against a. pair of nutsBl threadedthereon, En-- 5 gaging the rear end ofllthismspringjsthe 1ow-er end of a lever 88' fulcrumedat 89Lon the frame of. the. machine, the upperend=o this leverl 88" carrying a cam follower 90. riding. in acam groove 9| of a cam drum 92'fi'xed toltheoverhead cam shaft 93 by the rotation otwhichmany; of' the machine operations are controlled} as J's-well. known in the art.

The axial motion of the tool-spindle..also-acts.. to controlthe. clamping andmeleasing oflthe nut segments. To thisiend; the spool 4'6.=is engagedby a yoke 95 Tslidably, mounted on a stationary bar, 9'! between a pair of Iliinit collarsl Mand 95. fixed thereon. .When theiyoke fi is moved. rear.-

wardlyinto the positionflsholwn inlFigurel, the: 2

yoke 96l'is stopped by impingement-againstthe collar 95 so that the spool 43 is movedv to the position shown in Figures 8 .and 12,.forcing thenuttsegmentsto their inner/operative positions.- When the yoke 96 is moved..forwardly, r itfirst brings the nut segments. into engagement with the threaded portion 21, oF-igurel9, .showinglthese parts just before meshingrelation, theadjacent portions being taperedas. shown so as tofacilitate proper engagement,. andlwhen thel nut segments. do take hold, further .forward .motionof the. tool'.' spindle is controlled by, such engagement, the-link 85' sliding thereafter, if need.be, relativewto the lever 88. After thBItOOI has-cut. threads .to the desired depth and had. been .freeditherefrom, as willlater appear, the yoke 93'. engages the stop collar 94, retracting thespool.dfirlfromlthe position shown in Figures .8 andll'2'andl allowing the segments to springo'utwardlyout of lcontact with W the leadscrew.

Threading tools which" may belemployediorl cutting threads, as by. the lead screw and... nut segments, are illustrated in Figures .4 to 19; In Figures 1 to 7; the tool'is shown as--a rotary milling cutter I 03 arranged; tocut. internaliv threads in the work piece. The sl'eeve l5" which surrounds the spindle 24' is rotatably supported. in a bearing I"boltedto ai-stationary, frame member IOI. At its oforwardf'end' the spindle 24 receives thereinto a, tubular. shank. I35iof iatool" carrying head.l06; the shank being secured as. by a screw andcheck .nut I04. This-head;. I06-. has a portion Ifi'i'fof' a diameter intermediate to that of the forward portion anduth'elshankl I05," and on this is axiallyrsli'dable a spoolLIflllprovided with a cross pin I09extending through a slot H0 through the portion I'O'l'and which extends through a hole III in asleeve- II2\and through a headedshaft I I3 within. the :sleeveI I2. The shaft H3 and the sleeve ll2 .thuslmay slide axially with respectltdtheishankl. I05 and the spindle 24 to an extent limited lbyithel lengthof the slot H0.

The head I06 jcomprisesa pair of membersrl I5 and I Itwhich are secureditogether asby. screws III (see Figurefi). The.memberlII6 hasaforwardly projecting webs I I8'I-to which issecured, as by screws H9, thelcover-plate-120. Back of the cover platev and. between angular-bearing rings I2I and IZZ'thereisjournaled a.--ring I23 which has an internal gear-oportionnl24-fl Meshing with thisgear portion- I24-is a gear I26- carried'l by a pivot pin I21,. whichis journaledin the cover plate I20 and aacross:partition-portion I29 o..the member= I I6: Thisspint I21 ihasvfu 6;- crumed thereon: aapairof,- arms: I30: and-l I'3iI at? either; side otthe geanIZfiz. 'Ihegear 12 t imeshese with a.- pinion-134mm a tooltspindle [33$ This; spindle I 33 is j ournaled in suitable ibushingamhe; one in the arm 7 I 3 I and thel-other in? hub r I35: of the arm a I 3 0; and which extends: out Y through aslot I35 through the1 :'face plate t20-;zas: shown best in Figure 2; Theearm I 30: has: aethickened portion I 40r-whi'ch -v.engages thexfa-ce: of: the arm I31 2 (see Figureszdandto) and itisz-secured -thereto as'by means-ofviscrews: Mi -and ai -pint I43: The pin I 43-,e'xtends through a: curved slot I44 through theocross web F I29 of thel member- H6 and'zthrough a straight! slot I 46 through a disk'i I 4-Ia'whichsisr j ou-rnaled within w a: rim: I482extendingfrom az-second: disk I 49.- The io'rwardxdisl: V I 4?I--is,provided withaepair ofspace'dbush-ed holes- I 50 therethrough withirr which may; extend the forward .ends-of-a'--p,air "of:plugs5e I 5I having; com-:

seated in: suitable: openings' -in; as ring? I 54- posi-- tioned=back of the: diska I 49: and:;seated:in.' cylindrical housing-5 I53: in the-head: portion I .I 5 The ring-member I54 is engagedby; the head I 55 of the shank.- member I I3; .so r-thatzwhen this shank memberriseretracted it is moved;there with andpulls theplugs I51 backwardly,rbringing their forward'ends out10f registryrwithin the hushed-openings I50 ofthe rdisc; I47: This per 30:- mits a spring: I seated ina.-curved slot: IEiI- (see Figure7) in thedisk I49 andtengaging; a;- pin I 63v projecting into this slot from the-r disk I41 to' cause'lim'ited. rotationsof the? disk; I41, which acting upon l-theipin- I43; rocks thezarms 35:: I30 and I3 I ma direction to movethevtool spindle I 33 inwardly 'inthe slot I 36-vaWayrfrom the inner face of the work. piece and inwardly from the position shown inFigure 2; Thespindle: I33-may be forced outwardly in this-slotv by: forcing? the 40 conical ends: I 52 of the plugs I5 I into the hushed openings "I 50; and the: extent-to 1 which this f-tool' spindle is moved outwardly: is: dependent uponthe angular position of the disk I49:.rr'elative :to' the-tool head; This isadjustable'by' means: shown inFigure.=7; The-rim l'48 of this di'sk I 49 is provided at 1 one portion;- of: its periphery with worm teeth as shown lat I*65 :in Figure -7- and with theselteethi'there-meshes a worm I66 journaled in the member I I6- and -accessi'bla at' one end" for" turning' by a -suitable -tool (not shown) whichreng'ages in a socket' IB'I in its outerend. This socketde'l' is -in"=a headI68 shown as provided with graduations so that 'the angular position ofi'this worm atany time can be readily determined; When-the angularlposition of the disk I 491has been adjusted to the desired posi-" tion it may? be locked in this'positionby 'tightening a -screw I'm-threaded at I'II 'into'the member I I Gand extending through a bushing- I'IZslabbed off on one side as at I'l3 'whereitmay act asa clamping brake shoe contacting withth'e-rim I 48; When the spool I01'is in its forward'position shown in Figure-h the tool'spindle l33 is in its outer position where the millin'g tool I03 carried 5 thereby is inposition toact on th'e worki When the threadrcutting has been done-to'th'e desired depth, the spool I08'is held from furtherfor-w-ard motion with the tool head, which causes a retraction of the pins I5'I, finally releasing the member I33 ,for retraction" from; the work preparatoryito backing ofi;

The: internal gear ring-I 23 is held rtrom rotation with the spindle '24,: and for lthis'spurpose it" may be provided with a lfork 1 I lB whichsrislidably, i

engagesarail I19 boltedlto;theotool:c'arrierw iin longitudinal T slots with which this tool carrier is provided, as previously described. The spool I08 is engaged by a yoke I80 slidable axially on the rod 91 between the fixed stops I8I and I82. When this yoke contacts the rear stop I82, further retraction of the work head moves the milling tool outwardly into operative position, and when it contacts the stop I8I on the forward motion of the milling cutter, it acts to retract the plugs II causing automatic retraction of the milling cutter from the work. The parts are so set that as the threading tool is advanced from its retracted position toward the work, the first part of this motion is done by the action of the cam 92, under resilient pressure. When the tool comes near to the work, the nut segments come into engagement with the threads of the lead screw so that further feed motion of the tool is under control of the lead screw and nut. The tool is now in its outer position and is rotating so that it engages the work, rotating about its own axis and at the same time turning about the interior of the work piece-and progressing axially, the relative rotations between the tool and the work being as shown by the arrows in Figure 3.

When the threading has been done to the desired extent, the yoke I80 is stopped by impingement upon the fixed collar I8I, this acting to release the threading tool so that it snaps toward the axis of the work and away from cutting relation thereto. Next, the lead segments are freed from the lead screw by the action of the yoke 96 on the spool 46 so that the lead nut segments spring out of contact with the lead screw and the positive forward feed of the tool is stopped. The cam 92 then takes over and retractsthe tool substantially axially away from the work and while out of contact therewith. Adjacent to its retractive limit of motion, the yokes I80 and 96 contacting with their respective stationary collars I82 and 95, respectively, close the nut segments to their operative positions and swing the cutting tool out to its threading position so that on subsequent advance of the tool, when it, next reaches a work piece, it begins to cut the threads thereon.

In Figures 13 to 16, a modification of the tool head is illustrated in which a rotary thread cutting mill is arranged to cut external threads. The member H5 is like the member II5 shown in Figures 4 and 5, but adjacent thereto, the member 200 is substituted for the member H5. This member 200 has an arcuate web I extending forwardly therefrom to which is secured, as by the screws 202, a cover plate 203 having a slot 264 therethrough. Journaled between the rear face of the cover 203 and the member 200 is an internal ring gear 205 with which meshes a gear 206 journaled on a pin 201. This pin forms a rocking axis of a pair of arms 208 and 209, the arm 203 being pinned to the fulcrum pin 20?. The gear 206 meshes with a gear 2I0 on a cutter spindle 2 which is journaled in the arms 208 and 200. The arms 20B and 209 have a pin 2 I 5 which rides through a curved slot 2H5 in the transverse wall member 2I'I of the member 200 and also passes into a straight slot 2I9 in. a disk 220. This disk220 is journaled within the flange 22I of a disk 222, and the disk 222 is arranged for angular adjustment as by rotation of a worm 225 and is locked in adjusted angular position by locking mechanism similar to that shown in Figure 7. The ring gear 205 is held. against rotation as by the guide 224 similar to the ring gear I23, by the guide I18 and as the spindle 24 rotates, the head rotates therewith so that the gear 206 rotates in planetary relation to the internal gear 205. A plug 226 with a tapered end 221 is slidably guided through the disk 222 and its inner tapered end may bear within a sleeved opening 230 in the disk 220. The rear end of the pin 226 is secured in a ring 23I which is employed in place of the ring I54 shown in Figure Q.

When the plug 226 is in the axial position shown in Figure 13, its tapered end engaging in the opening 230, the thread cutting mill 235 carried by the spindle 2 is in its inward position shown in Figure 14, but by pulling rearwardly on the ring 23I, the plug 226 is pulled out of its locking position and the mill is moved outwardly away from the periphery of the work by a spring 240 seated in an arcuate slot MI in the disk 222 and engaginga pin 24l0 projecting from the disk 220. The action of this mechanism is similar to that previously described, with the exception that the thread cutting mill is moved inwardly to operate on the work instead of being moved outwardly, and it moves outwardly when released to free the work instead of being moved inwardly to release it, as in the case of the internal thread milling cutter.

In Figures 17, 18 and 19 a further modification 1 is shown in which a non-rotating chaser 250 is employed for cutting internal threads. The members H5 and IIS of the construction shown in Figures 4 to 7 are here employed, but in place of the ring gear I29, the front cap 255 is provided with an annular flange 256 which directly engages the forward face of the member II6 around its periphery. The disks I41 and I48 may be used as in the construction of Figure 4, together with their locking plugs and spring mechanism for throwing the cutting tool out of operative position. The cutting tool, which is shown as a non-rotary chaser, is fixed to a tool post 260 and locked by mating serrations 258 (Figure 23) on the chaser and the tool post, which post is carried by an arm 26I journaled on the arbor 282, which extends between the cover plate 255 and the member H6. The arm 26I carries the tool post 260, as shown in Figure 19, and also a pin 264 which extends through the arcuate slot 263 of the part I I5 and into the straight slot 261 of the disk I41. The action of this head is similar to that shown in Figures 4 to 7, except that the tool is not rotated about its axis, but is given a gyratory motion as the tool spindle rotates while the work spindle is rotated as shown in Figure 18.

In some cases it may be desired that the thread cutting tool shall not be moved laterally into operative position on retraction of the tool head, but that it shall be held retracted until the tool has been advanced axially to about the point where it is desired to start the thread cutting operation. This will permit internal threading of a portion of the work piece of larger internal diameter than nearer. to the mouth of theopening in the work piece aS shown in Figure 21, the work piece being shown as provided-with a reduced diameter portion 210, or the externalthreading of a portion of a Work piece 'of smaller diameter than a portion nearer to the starting end of the work piece as shown in Figure 22, in which there is an external larger diameter shoulder'215. When this is desired, the cam actu'ated'lever 88 maybe provided with an extension 300 pivotally supporting a 9 at its lower "end a swivel stud 301, :as shown in T'Figure 29, this stud :being slidable one. rod 302 between pairs "of checknuts "3li-3' and 306 thread- .ed thereon. The forward end :of the *rod 302 is pivoted at 385 to a yoke 3,116 which takes the --5 grilace of the yoke 13d shown in Figure 1. The stop collar [8213f Figure 1 is omitted'from the bar "'91 that'the tool is. not returned laterally to operative position whenthe'tool head is retracted. (9n 'the subsequent forward swing of -10 thelevertirl, which advances the tool head, the :lower end of the extension 3300 travels "faster than theitool 'headfbing further from the ful- -cr1nn"8'fi, and also faster than the feed from the fleadfscrew .if this-is engaged, "so that when its 1 5 movable laterallyof said work holding spindle "stud 3D! impinges gonthe nuts303, it=moves the *rod 3fl2fon vardly-relative to the tool head and "moves the spool "108 relative to this head to "the le'ft,'wliicl'i*moves "the tool laterally into -,cutting relation to theworkpiece. Eitherthe stop cdllar I85! on-whichthe yoke 306 mayimpinge, --or thenuts d ioniwhichgthe 'swivel stud 36! may impinge .011 reverse motion of the lever '88, may

=be employed to release the tool to spring latferallyaway frcm the workwhen thread cutting 555 has proceeded to "the desired point.

,From the foregoing description of .certain embodiments of "this invention, 'it'will be understood 'by .those s'killed -in the .art that various q further nha-nges and "modifications might be made Without departing 'from'its spirit or scope.

'1. In combinationwith'a rotary'work spindle, of a tool spindle arranged ,coaxial with said work :spindle and Totatably and axially movable, .a 'ihollow -rotary shaft coaxial with said tool spindle, ,means supporting "said shaft against axial motion, ,a :collet within said shaft, said shaft having a "tapered bore cooperating with 'said CO119t to close said collet by axial motion ""40 of said collet 'in 'one direction and permitting said collet to open on motion of said collet in t e opposite direction, means for so moving said aaol'letga lead-screw having a-shank portion adjustable axially 'through said -collet and ar- &5 ranged two "he gripped therebyywhen said collet 'is closed, a nut segment carried by said tool -'s pindle."'forilateralmotion intoand out of driven relation'to said leadgscrewsand'held against ax- -ial1motion relative "to said 'tool spindle to cause raxial mo'tion 'of said tool spindle when said segtnentis insaidirelationand said lead screw is rotated relative 'to said tool spindle,means for -'so rotating said shaft andlead screw, and 'thread'cuttirigtool carried by said tool spindle for "cutting threads on "work carried by said work-holding spindle {during such rotation of "said shaft "and *lead screw.

In combination with a rotary work spindle, of atool spindle arranged in the direction of said work spindleand movableaxially, a rotary shaft extending in the directionof said spindles but held against aixial-motion, a lead screw rotatable with said shaft, a nut segment carried by said N tool spindle .andmovableiinto and out of driven relation to said lead screwand causing axial motion of said'tool spindle by rotation of said'sorew iW-hensaid segment is in drivenengagement'therewith ands-said shaft is rotated relative to said tool spindle, a tool carried hysaid toollspindle rand nnovable laterally of .said work holding spindle into and out of .operative relation to work carried by said work holding spindle, and means for moving said segment into engagement with said lead screw while said tool is in advanced povsition and for first retracting said toolfrom advanced-position and-thereafter moving said segment out of engagement with said '-lead screw.

3. In combination'with a;rotary work-spindle, of a tool-spindle arranged in the direction fsaid Work spindle andsmovableaxiallma rotary-shaft extending in the direction of said spindles but held against axial-motion, a head screw rotatable with said shaft, anut-segment carried-by said tool spindle and 'movable'into andout-of driven relationto said lead screwand causing axial motion of said tool spindle'byrotation of said screw when said segment is in driven engagement therewith and said "shaft is rotated relative to said tool spindle, a tool carried by said tool spindle and into and outgofoperativerelation to work-carried by said work holding spindle, means for moving said se ment ;into engagement with said lead screw While said "tooliis in advanced position and for first retracting's-aiid tool from advancedpositionand thereafter moving "said segment out-of engagementwith said lead screw, said tool being a rotary tool; means driven from said-tool spindle for.rotating said tool, and means for mtating said tool spindle.

4. In combination witha work spindle, a tool spindle extending -in the "same direction :as said work spindle and' novable axially, atoolhead at one endof said tool spindle, means supporting saidhead for axialibutrnonerotary motion, -a rotary shaft havingits axis extending in'the .directionof said spindles and held against axialmotion, .a lead. screw carried bysaid shaft and ."co-

.axial Withsaid tool spindle, anutLelement carried by said ;tool spindle and movable laterally .of its axis into and outof cooperativerelation to saidscrew, a threading 'tool carried "by said head and mounted fonmotion laterally of said axis, tmeans for advancing said head *yieldingly to .bring said 'tool'toward operative axial relation to work carried by said workispindle and for moving said nut element .into cooperative relationto said screw whereupon further -advance of said ,head'is controlled by said screw and nut element, andgmeans for moving'saidtool laterally ofsaidaxis 'out;0f cuttingrelati'on to the work after a predetermined amount of thread cutting by said tool.

5. In combination'with a workspindle, a tool spindle extending in the same direction assaid work spindle and movable axially, a tool head at one end of said tool spindle, means supporting said head for axial but. non-rotary motion, a rotary shaft having its axis extending in the direction o'frsaid spindles andheld against axial motion, a lead screw'oarried'by said shaft and coaxial with said tool spindle, a nut-elementcarried by. said todl "spindle and movable laterally of its axis into ,an'dlout .of cooperative relation .to said ,screw, 5a threading tool carried by said head and mounted ."for. motion laterally of .said axis, (means (for advancing said ,head yieldingly to .bring said .tool toward operative axial relationto worlncarriedloy.said'work spindle .andfor moving said -nut ,element into cooperative .relationto .said screw whereupon further advance of said .head .is-contro.lled .bysaid screw .and .nut element, andmeanseffectiveatthe end ofthe desired threadcutting tofirst .movesaid toollaterallyout of cutting (position andithen a'etr-act said nut .element from .said .lead screw. and then retract said'head.

6. In combination with a rotary work holding spindle, a rotary tool spindle extending in the 11 same direction as said work holding spindle and movable axially, a tool head at one end of said tool spindle, means supporting said head for axial but non-rotary motion, a rotary shaft having its axis extending in the direction of said spindles V and held against axial motion, a lead screw carried by said shaft and coaxial with said tool spindle, means for rotating said tool spindle and shaft at different speeds, a nut element carried by said tool spindle and movable laterally of its axis into and out of cooperative relation to said screw, a rotary threading tool carried by said head and mounted for motion laterally of said axis, means for advancing said head yieldingly to bring said tool toward operative axial relation to work carried by said work spindle and for moving said nut element into cooperative relation to said screw whereupon further advance of said head is controlled by said screw and nut, means effective at the end of the desired thread cutting to first move said tool laterally out of cutting position, then retract said nut from said lead screw, and then retract said head, and means actuated by rotation of said tool spindle to rotate said tool.

7. In combination with a rotary work holding spindle, a rotary tool spindle extending in the same direction as said work holding spindle and movable axially, a tool head at one end of said tool spindle, means supporting said head for axial but non-rotary motion, a rotary shaft having its axis extending in the direction of said spindles and held against axial motion, a lead screw carried by said shaft and coaxial with said tool spindle, means for rotating said tool spindle and shaft at different speeds, a nut element carried by said tool spindle and movable laterally of its axis into and out of cooperative relation to said screw, a rotary threading tool carried by said head and mounted for motion laterally of said axis, means for advancing said head yieldingly, to bring said tool toward operative axial relation to work carried by said work spindle and for moving said nut element into cooperative relation to said screw whereupon further advance of said head is controlled by said screw and nut, means effective at the end of the desired thread cutting to first move said tool laterally out of cutting position, then retract said nut from said lead screw, and then retract said head, means actuated by the retraction of said head to advance said tool laterally into cutting position, and means actuated by rotation of said tool spindle to rotate said tool.

8. In combination with a rotary work spindle, a tool spindle arranged in the direction of said work spindle and movable axially, a rotary shaft extending in the direction of said spindles but held against axial motion, a lead screw rotatable with said shaft, a nut segment carried by said tool spindle and movable into and out of driven relation to said lead screw and causing axial motion of said tool spindle by rotation of said screw when said segment is in driven engagement therewith and said shaft is rotated relative to said tool spindle, a tool carried by said tool spindle and movable laterally of said work-holding spindle into and out of operative relation to work carried by said work-holding spindle, means for moving said segment into or out of position to engage said lead screw and for moving said tool laterally of the work to and from operative position in timed relation to each other and in deried by said work spindle and for moving said sired axial position of said tool, said tool being a rotary tool, means driven-from said tool spindle for rotating said tool, and means for rotating said tool spindle.

9. In combination with a work spindle, a tool spindle extending in the same direction as said work spindle and movable axially, a tool head at one end of said tool spindle, means supporting ,saidhead for axial but non-rotary motion, a

rotary shaft having its axis extending in the; direction of said spindles and held against axial motion, a lead screw carried by said shaft and coaxial with said tool spindle, a nut element carried by said tool spindle and'movable laterally of its axis into and out of cooperative relation to: said screw, a threading tool carried by said head and mounted for motion laterally of said axis, means for advancing said head yieldingly to bring said tool toward operative axial relation to work carried by said work spindle and for moving said nut element into cooperative relation to said screw whereupon further advance of said head is controlled by said screw and nut element, and means for moving said tool laterally of said axis into or out of cutting relation to the work at predetermined positions of said tool head.

10. In combination with a rotary work holding spindle, a rotary tool spindle extending in the same direction as said work holding spindle and movable axially, a tool head at one end of said tool spindle, means supporting said head for axial but non-rotary motion, a rotary shaft having its axis extending in the direction of said spindles and held against axial motion, a lead screw carried by said shaft and coaxial with said tool spindle, means for rotating said tool spindle and shaft at different speeds, a nut element carried by said tool spindle and movable laterally of its axis into and out of cooperative relation to said screw, a rotary threading tool carried by said head and mounted for motion laterally of said axis, means for advancing said head yieldingly to bring said tool toward operative axial relation to work carnut element into cooperative axial relation to said screw whereupon further advance of said head is controlled by said screw and nut, means for then moving said tool laterally to bring said tool into lateral cutting position, means effective at the end of the desired thread cutting to first move said tool laterally out of cutting position, then retract said nut from said lead screw, and then retract said head, means actuated by the retraction of said head to move said nut element into cooperative lateral position, and means actuated by rotation of said tool spindle to rotate said tool. I

HERBERT H. RANNEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,877,056 Rupple Sept. 13, 1932 2,069,098 Rupple Jan. 26, 1937 2,161,548 Miller June 6, 1939 2,266,338 Sheaffer Dec. 16, 1941 2,376,164 Miller et a1 May 15, 1945 2,451,497 Kratchman Oct. 19, 1948 

